¹⁸F-Trifluoromethylation of Unmodified Peptides with 5-¹⁸F-(Trifluoromethyl)dibenzothiophenium Trifluoromethanesulfonate

Abstract

The ¹⁸F-labeling of 5-(trifluoromethyl)-dibenzothiophenium trifluoromethanesulfonate, commonly referred to as the Umemoto reagent, has been accomplished applying a halogen exchange ¹⁸F-fluorination with ¹⁸F-fluoride, followed by oxidative cyclization with Oxone and trifluoromethanesulfonic anhydride. This new ¹⁸F-reagent allows for the direct chemoselective ¹⁸F-labeling of unmodified peptides at the thiol cysteine residue.